In networks, such as wireless networks, it is desirable to allocate network resources according to policies or rules. These policies cover resources, such as network bandwidth, Quality of Service (QoS), and security (firewalls). With some types of content, such as web surfing, latency and packet loss might not significantly affect the quality of the content delivered, and the effect might not be noticeable. However, as the types of content delivered to mobile subscribers (e.g., cell phones, personal digital assistants (PDAs), and other handheld devices) become more diversified to include Voice over IP (VoIP), streaming media, and multiplayer gaming, these types of content require reliable network connections with fixed parameters. With content like this, delays and out-of-order arrival can be more significant.
A network with policy-based management uses rules to govern various aspects of the network behavior. Networks implementing policy-based management typically use a protocol for handling authentication, authorization and accounting (AAA) services. Two such protocols are Remote Authentication Dial-In User Service (RADIUS) and Diameter. Authentication refers to the process where an entity's identity is authenticated and matched to a user record, such as the mobile subscriber record for a user of a cellular telephone. Once the subscriber record has been identified, an AAA server may permit application services to determine whether the user is permitted to access certain services (authorization) and to record the activities of the user (accounting). One use of accounting is to be able to provide data in a form that is suitable for billing. These protocols may be implemented by one or more servers whose purpose is to provide AAA services. Diameter is a next-generation protocol intended to replace RADIUS as the AAA method of choice in next-generation cellular networks.